1. Field of the Invention
The present invention relates to a retractable nail device, more particularly to an attachment device to any solid, fibrous or cellular materials or the like, including wood, metal, plastic or composite materials, which can be retracted without destroying the material to which the retractable nail device is inserted into. In particular, the helically threaded portions of the device are covered or filled with a plastic material, epoxy, glue, composite or the like to prevent damage to the helically threaded portions of the device when the device is hammered or bored with a pneumatically or electrically powered nail to any solid, fibrous or cellular materials or the like, including wood, metal, plastic or composite materials.
2. Description of the Related Art
The wood floor nail 3 of FIG. 12 and the wood floor staple 13 illustrate prior art attachment devices that are used to attach wood floor boards to the sub floor, in the manner similar to the illustration of FIG. 11. The wood floor nail 3 has a main head 30 and a main body 32, lateral extensions 34 on front and rear sides of the main body 32, and a tip 35. The wood floor nails 3 are generally placed in a magazine clip attached to a pneumatically or electrically powered nail gun. The nails 3 are readily inserted into wood floor boards, with the main head 30 anchored to an outer surface of the wood floor board, but the nail 3 can not be easily removed. In the event that one has mistakenly inserted the nail 3, there is no easy means of removing the nail 3. Somehow the main head 30 must be grasped and pulled, causing damage to the delicate wood floor board, and the lateral extensions 34 that act to retain the nail 3 into the wood floor board and sub floor will destroy or at least significantly damage the wood floor board, as well as the sub floor when the nail 3 is pulled out. The lateral extensions 34 are not part of any helical screw thread and therefore, rotation of the nail 3 will not form a screw bore/helical thread bore that would permit the escape of the nail 3 out of the wood floor board and sub floor without significant damage to the wood material.
The wood floor staple 5 of FIG. 13 is also used to attach wood floor boards to a sub floor. The staple 5 includes a pair of legs 55 and a connector 52 connected to the legs 55. The staples 5 are usually placed in a magazine feed attached to a staple gun and the legs 55 are stapled into the wood floor board and sub floor, in a manner similar to the nail 1 shown in FIG. 11. The connector 55 rests on the wood floor board at a location similar to the main head 10 of the nail 1 in FIG. 11.
The problem with the staple 52 is that the connector 52 tends to strongly impact the wood floor board, often shearing off pieces of the wood floor board on impact and thereby destroying the wood floor board. The use of a staple gun is not recommended when using brittle wood material or expensive materials, such as aged wood or the like. The staples 5 are easily dispensed but in addition to the disadvantage mentioned above, the staples 5 can not be readily or easily removed. If the staple 5 is applied incorrectly, the connector 52 must somehow be grasped and pulled to try to remove the staple. This is a highly time-consuming process which may lead to irreparable damage to the wood floor board.
Ordinary screws (not shown), such as wood screws, have a helical thread that spirals from at or near the piercing tip towards the head portion along its longitudinal length around a main body or shaft, as in the wood screw of U.S. Pat. No. 4,572,720. Such screws generally have a tool receiving slot for receiving a retracting tool such as a Phillips head screw head, Allen wrench, or the like, and are attached to a material by using a power tool that rotates the retracting tool which has been inserted into the tool receiving slot of the screw head. A helical threaded bore is formed in the material when the screw is inserted via rotation thereof. Such procedure also enables the screw to be retracted (via counter-rotation, leaving behind the helically threaded bore) without any significant damage to the material such as a wood floor, but the insertion by screw rotation of individual screws is highly time-consuming and labor-intensive, which significantly adds to overall building costs, i.e. laying wood flooring.
Furthermore when ordinary wood screw is driven into a wooden board, it is known that the wood shavings fill the grooves formed between adjacent screw thread sections on the shank portion as the screw threads cuts into the fibers of the wooden board, thereby resulting in a binding force between the screw and the wooden board. However, because the cutting line is in the form of a smooth spiral line, the cutting effect of the screw thread becomes duller as the cutting effect of the screw thread becomes duller as the depth of penetration of the conventional wood screw into the wood board increases. In addition, the increased resistance can have adverse affect on the required screw driving force and can result in possible damage to the screw.
Therefore, there is a need for an attachment device that can be quickly and easily be inserted into wood material or similar materials (i.e. via a nail gun), but which can be removed without significantly damaging or destroying the material while maintaining the integrity of the helically threaded portion of the device.